Rotary fluid-pressure machine



Feb. 2, 1965 J. KRUDEWIG ETAL 3,168,051

ROTARY FLUID-PRESSURE MACHINE Filed March 29, 1963 5 Sheets-Sheet 1 JOHANNES KRUDEWIG HERBERT SICK Jn venfor' AGENT Feb. 2, 1965 J. KRUDEWIG ETAL Filed March 29, 1963 5 Sheets-Sheet 2 1 n 14 p T fi 25 g2, 553w J 20 k JOHANNES KRUDEWIG HERBERT SICK Jn venfor.

Feb. 2, 1965 J. KRUDEWIG ETAL 3,168,051

ROTARY FLUID-PRESSURE MACHINE Filed March 29, 1965 5 Sheets-Sheet 5 INVENTOR. F g- 4 JOHANNES KRUDEWIG HERBERT SICK AGENT United States Patent ()fifice 3,168,051 Patented Feb. 2, 1965 9 Claims. (cl. 103-202 Our present invention relates to rotary fluid-pressure machines or hydraulic drives and, more particularly, to machines capable of operating either as pumps for the displacement of fluids under pressure or as motors driven by a pressure fluid.

Earlier machines of this type generally comprise one or more rotor assemblies each of which can operate as a pump or motor unit. The rotors may be of the radial-vane or piston type with fluid being supplied to the assembly by means of axially extending passages formed in a shaft about which the rotors are angularly displaceable. More recent developments in machines of this character have led to arrangements wherein the axial conduit supplying the rotor means, and the rotor means itself, are frequently mounted for at least limited radial displacement within the housing. The rotors generally cooperate with rotatable casings defining the working chamber of the pump and/ or motors. To eliminate seizing of the rotors upon the axially extending conduit or so-called distributor shaft, this nonrotatable member was also mounted in the housing with freedom of at least limited radial motion, and frequently carried the weight of valves, controls and other elements serving to supply fluid thereto.

In such arrangements, there is frequently a one-sided load upon the conduit as a consequence of the connecting devices employed to supply fluid under pressure thereto, pressure-responsive valves carried thereby and/ or control devices used to throttle or regulate the input or output of fluid under pressure. These unbalanced loads, which vary from time to time depending upon the appliances used in conjunction with the machine, cannot be easily compensated for by balancing the conduit in manufacture. As a consequence, it has been common heretofore to expect a certain amount of binding, loss of fluid pressure and strain upon the relatively rotatable parts of the device. Earlier constructions were also disadvantageous in that they did not permit of a ready assembly of the several components or their incorporation with ease in multi-section housings.

It is an object of the present invention to provide an improved rotary fluid-pressure machine of the aforedescribed character wherein the enumerated disadvantages and others readily apparent to persons skilled in the art are obviated.

Another object of this invention is to provide a fluidpressure machine wherein the rotor and conduit means can partake of at least limited radial movement without undue load being applied to the conduit.

These objects are attained, in accordance with the present invention, in a fluid-pressure machine wherein the rotor means is journaled with respect to an axially extended conduit or distributor shaft, whose axial passages communicate with one or more fluid-transmission means joining these passages to fixedly positioned connecting means. By connecting means it is here intended to designate all arrangements for supplying fluid to and removing it from the radially extending transmission means and, therefore, encompass all of the usual control appliances (e.g. regulating valves, pressure indicators, bypass-arrangements and the like) in addition to simple conduit connections, for the supply and discharge pipes. The essential feature of the present invention is that the fluid-transmission means, which may be tubes rigidly fixed to the axial conduit, is flexibly coupled with the aforementioned connecting means. This arrangement permits at least limited radial displacement of the conduit without undue mechanical loading thereof, since, in contradistinction to earlier arrangements, the conduit does not carry any of the valves, connectors, control elements, bypasses and like devices which earlier systems disposed thereon. The yieldable junction between the transmission means and the connecting means nevertheless insures a positive transmission of fluid to the rotor means.

While the flexible and, advantageously, resilient coupling of the transmission means with the connecting means can make use of elastically deformable (e.g. rubber) transmission tubes, it is often desirable to form the transmission tubes as rigid elements whose free extremities terminate within the housing. The connecting means may thus be provided upon the housing and can include respective fluid chambers into which the transmission tubes extend. According to a more specific feature of the invention, the annular walls of such chambers surround the tubes with peripheral clearance, a resilient sealing ring being interposed between the wall and the tube in each clearance for closing the joint with respect to fluid under pressure while permitting relative axial movement between the chamber wall of the connecting means and the tube.

Still another feature of the present invention resides in providing the generally radial sump-intake tubes of the machine with unidirectional valve means which is not carried by these intake tubes but rests upon the floor of the sump but receives the tubes with freedom of relative axial displacement. Again, annular sealing members may surround the intake tube and engage the valve means for insuring a fluidtight joint therebetwcen while permitting such axial displacement. It is clear that this construction eliminates the strain on the conduit means deriving from the weight of similar valve arrangements employed in earlier rotary machines. In each case, the sealing rings provide a guide for the radial tubes so that assembly of the housing and, in general, construction of the assembly, is facilitated.

The above and other objects, features and advantages of the present invention will become more readily apparent from the following description, reference being made to the appended drawing in which:

FIG. 1 is an axial cross-sectional view through a rotating pump-and-motor arrangement according to the invention;

FIG. 2 is a cross-sectional IL-II of FIG. 1;

FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 1; and

FIG. 4 is a view similar to FIG. 2 showing a modified rotary machine of this type.

In FIGS. 1 through 3, we show a fluid-pressure machine whose housing 1 is shown to be of unitary construction although it is clear that it can be, if desired, formed from a plurality of parts. As a conventional device of this type the machine includes a first rotor assembly A which can be employed either as a pump or as a rotor and a symmetrical rotor assembly B, axially spaced therefrom and likewise capable of such dual function. Each of the rotor assemblies includes a sleeve 2 journaled in bearings 3 within the housing 1. The sleeve 2 is keyed to a stud shaft 4 which extends axially from the housing and can be employed either to drive the respective rotor assembly or as a power-takeoff shaft to derive rotary motion therefrom. Since both of the rotor assemblies are identical it ew taken along the line 'the weight of these valves.

3 suffices to describe only one of them. The sleeve 2 carries the rotor 5 which in the present case is shown to be of the radial vane type provided with vanes 5' although radial piston rotors can be similarly, employed. The rotor forms with casing6, 6 a pump or met-er chamher. The casing 6, 6' is journaled within the housing in bearings 7 of a bearing carrier 8 This carrier is provided with pivots 8', 8" so that it can oscillate as indicated by the arrow 8a. Such arrangements are known tfiler se and there is no need for further detail concerning Both rotor assemblies A andB are linked bya nonrotating conduit shaft 9 extending coaxially with respect to the rotors. This conduit is provided with two generally axial passages 10 and 11 which communicate with the working chambers of both assemblies in the conventional manner. One of the passages is, of course, the suction duct while the other is a pressure duct. Centrally disposed along cylindrical conduit 9, is a rectangular body 12 through which the passages communicate with the fluid-transmission means. Pressure-transmission tubes 13 (FIG. 2) are thus readily seated in body 12 against washers '13 While suction tubes 14 extend downwardly into the sump formed at the base of the housing. 'Intake tubes 14 are set against washers 14' and are provided with unidirectional foot valves 15 as will be described in greater detail thereinafter. Each passage 19, 11 communicates with one of the pressure tubes 13 and one of the suction tubes 14 so that either passage can be employed for supplying fluid under pressure depending upon the external connections of the system.

The housing is provided with connecting means which includes a cover plate 17 whose connectors 18 communicate with chambers 16 into which the tubes 13 extend. The walls of these chambers surround the respective tubes with peripheral clearance while sealing rings 19 (e.g. of rubber) are disposed within the clearances to provide a tight fluid connection while nevertheless permitting radial displacement of the tubes 13. These rings also yieldably limit the displacement of the tubes against the chamber walls, but, in view of the dimensioning of the chamber, do not restrict the radial displacement of conduit 9 within the rotor assemblies A and B. The

plate 17 can carry one or more bypass valves 17' to interconnect the chamber 16 should a predetermined pres sure be exceeded in either of the transmission tubes 13. Valve 17' is, like the control block 17" (shown in dotdash lines) carried by the housing and in the tubeslS so that no mechanical force is applied by them to conduit 19; i

So that the depending tubes '14 also are not'mechanically rotated, the toot valves 15 are slidably mounted upon these tubes and are formed with cylindrical wall portions 20 surrounding the tubes and sealed with respect thereto by O-rings 21 or the iike. The valves15 thus rest against the floor 1' of the sumps 1" :formed in the housing below the level ofthe fluid 25 herein. This fluid level is maintained by an overflow bore-26. When the conduit 9 shifts radially the tubes 14 slide into and out of the respective valves 15 andthus do not carry By proper selection of the cross-section of tubes 13 and 14-. it is possible to eliminate any net mechanical force upon the conduit 9 by virtue of the hydraulic pressure within these tubes.

In FIG. 4 we show an arrangement wherein the tubes 13a and 14a have functions similar to those of tubes 13 and 14 except that they are inherently resilient as indicated by the exaggerated flexibilityshown. The resilient tubes can thus be fixedly connected withchamber 16 and valves 15 in any suitable manner. The flexible and resilient tubes again prevent any strain from being supplied to the conduit 9.

The invention as described and illustrated is believed to admit of many modifications within the ability of persons skilled in the art, all such modifications being considered within the spirit and scope of the appended claims.

We claim: h

.1. A hydraulic drive, comprising a housing; rotor means journaled in said housing for angular displacement about a common axis; nonrotating conduit means at least partly surrounded by said rotor means and mounted in said housing for at least limited radial displacement therein while being substantially coaxial with said rotor means and forming a fluid path therefor, said rotor means being rotatable relatively to said conduit means, connecting means fixed with respect to said housing and generally radially offset from said conduit means while forming a fluid pat-h communicating with said conduit means; and generally radial fluid-transmission means yieldably communicating between said connecting means and said conduit means for permitting said displacement of said conduit means. a 1

2. A hydraulic drive, comprising a housing; two rotors in said housing independently journaled for angular displacement about a common axis; a respective casing surrounding each rotor for-forming a fluid compartment therewith; "an axially extending nonrotatable conduit surrounded by said rotors substantially? coaxial therewith and having at least two axial fluid passages communicating with said compartments, first and second connecting means rigidly mounted on said housing and generallyradially offset from said conduit while providing fluid paths communicating with said passages, each of said connecting means being provided :with a generally radially extending annular wall enclosing a space; first generally radial fluid-transmission means yieldably communicating between said first connecting means and one of said passages; second generally radial fluid-transmission means yieldably communicating between vsaid second connecting means and the other ofsaid passages, each of said transmission means including anelongated pressure tube fixedly secured to said conduit at oneend, the other end of each tube being received in the respective space .and axially slidable therein relative tothe respective walls, said walls each surrounding the respective tube with peripheral clearance, and atleast one sealing ring disposed in each of said clearances for bridging each tube, and the respective wall w-hile permitting relative axial displacement thereof.

3. A hydraulic drive, comprising ,a housing; rotor means including a first and a second rotor independently journaled in said housing for angular displacement about a common axis; casing means surrounding each rotor for forming a respective fluid compartment therewith; a stationary axially extendingconduit surrounded by said rotor means substantially coaxial therewith and having at least. two; axial fluid passages communicating with said fluid compartments; .first and jsecondyfixediconnecting means on said housing generally radially, oflisetfrom said conduit While'providing fluid paths communicating with said passages, each ofsaidconnecting means being pro vided with a generally radiallyextending annular wall; first generally radial fluid-transmission means fixedly secured to said conduit and slidably received insaid first connecting means for communicating between said first connecting means and one of saidpassages; second generally radial fluid-transmission means fixedly secured to said conduit and slidably received in said second connecting means for communicating between said second connecting means and the other of said passages,.each of said transmission means including a pressure tube generally axially displaceable relative to the respectiveannular wall; and flexible sealing .means bridgingv each tubeand the respective wall while permitting relative axial displace.- ment, said housing forming a sump for said fluid; and suction means including at least'one. radial intake tube rigid with said conduit and communicating with arespective one of said passages while being limitedly displaceable radially ofsaid conduit.

4. A hydraulic rive, comprising a housing; rotor means including a first and a second rotor independently iournaled in said housing for angular displacement about a common axis; casing means surrounding each rotor for forming a respective fluid compartment therewith; axially extending conduit surrounded by both of said rotors substantially coaxial therewith and having at least two axial fluid passages communicating with each of said fluid compartments; first and second fixed connecting means on said housing generally radially offset from said conduit while providing fluid paths communicating with said passages, each of said connecting means being provided with a generally radially extending annular wall; first generally radial fluid-transrnission means movably communicating between said first connecting means and one of said passages; second generally radial fluid-transmission means movably communicating between said second connecting means and the other of said passages, each of said transmission means including a rigid pressure tube fixedly secured to said conduit and generally axially slidable relative to the respective annular wall, said annular walls each surrounding the respective tube with peripheral clearance, at least one sealing ring disposed in each of said clearances for bridging each tube and the respective wall while permitting relative axial displacement, said housing forming a sump for said fluid, suction means including at least one downwardly extending radial intake tube rigid with said conduit and communicating with a respective one of said passages; valve means on each of said intake tubes resting on the floor of said sump, said intake tubes being axially shiftable relative to the respective valve means; and an annular sealing member interposed between each of said intake tubes and the respective valve means while permitting relative axial displacement thereof.

5. A hydraulic drive, comprising a housing; bearing means mounted in said housing; two rotors each including a vane drum and a hub for each of said drums rotatably supported by said bearing means; a casing surrounding each of said drums for defining at least one respective fluid compartment therewith, each of said casings being adjustable eccentrically with respect to the respective drum; an elongated stationary distributing shaft extending between said drums and surrounded thereby, said distributing shaft being provided with at least two axial fluid passages in said distributing shaft communicating between said compartments, and generally radial fluid-transmission means rigidly secured to said distributing shaft and communicating with said passages while being supported by s. id housing with freedom of limited radial displacement.

6. A hydraulic drive, comprising a housing; bearing means mounted in said housing; two axially aligned rotors each including a vane drum and a hub for each of said drums rotatably supported by said bearing means; a casing surrounding each of said drums for defining at least one respective fluid compartment therewith, each of said casings being adjustable eccentrically with respect to the respective drum; means forming alternate radial slots and passages in each vane drum, a Vane slidably mounted in each of said radial slots; an elongated stationary distributing shaft extending between said drums and surrounded thereby while being generally coaxial therewith, said distributing shaft being provided with at least two axial fluid passages in said distributing shaft communicating between said compartments via said radial passages, and generally radial fluid-transmission means rigidly secured to said distributing shaft and communicating with said axial passages while being supported by said housing with freedom of limited radial displacement.

7. A hydraulic drive according to claim 6 wherein said fluid-transmission means consists of yieldable tubes.

8. A hydraulic drive according to claim 6 wherein said fluid-transmission means consists of a tube portion, a wall portion surrounding said tube portion, valves arranged in said wall portion, said wall portion bracing on said housing, said tube portion and said wall portion being slidable in axial direction respectively to one another.

9. A hydraulic drive as defined in claim 4 wherein said fluid-transmission means and said suction means are arranged radially of said conduit at diametrically opposite points thereof and at a location axially spaced from said rotors and situated therebetween.

References Cited by the Examiner UNETED STATES PATENTS 1,079,384 11/13 Wilson 103-12O 1,779,757 10/30 Streckert 103-136 2,307,851 1/43 Musick et a1 103120 2,653,549 9/53 Knight 103136 2,891,775 6/59 Malan 103136 X 2,975,716 3/61 Eickmann 103-136 X 2,977,039 3/61 Green et al 230158 X LAURENCE V. EFNER, Primary Examiner.

ROBERT M. VIALKER, Examiner. 

1. A HYDRAULIC DRIVE, COMPRISING A HOUSING; ROTOR MEANS JOURNALED IN SAID HOUSING FOR ANGULAR DISPLACEMENT ABOUT A COMMON AXIS; NONROTATING CONDUIT MEANS AT LEAST PARTLY SURROUNDED BY SAID ROTOR MEANS AND MOUNTED IN SAID HOUSING FOR AT LEAST LIMITED RADIAL DISPLACEMENT THEREIN WHILE BEING SUBSTANTIALLY COAXIAL WITH SAID ROTOR MEANS AND FORMING A FLUID PATH THEREFOR, SAID ROTOR MEANS BEING ROTATABLE RELATIVELY TOI SAID CONDUIT MEANS, CONNECTING MEANS FIXED WITH RESPECT TO SAID HOUSING AND GENERALLY RADIALLY OFFSET FROM SAID CONDUIT MEAS WHILE FORMING A FLUID PATH COMMUNICATING WITH SAID CONDUIT MEANS; AND GENERALLY RADIAL FLUID-TRANDMISSION MEANS YIELDABLY COMMUNICATING BETWEEN SAID CONNECTING MEANS AND SAID CONDUIT MEANS FOR PERMITTING SAID DISPLACEMENT OF SAID CONDUIT MEANS. 